我想买一台二手的激光打印机，选购时要注意些什么内容。鼓的好坏怎么看？碳粉是不是满的怎么判断？

我想买一台二手的激光打印机，选购时要注意些什么内容。鼓的好坏怎么看？碳粉是不是满的怎么判断？

打个测试页看看是不是能满足自己的需求 主要看看鼓芯如何 一般二手的碳粉都不会很多 鼓芯也用不了多久 能坚持多长时间就坚持多长时间吧 过后在换新的 长时间不用 一般不会有问题 最好不要闲置太长时间

最好别买二手的新的价格也不贵的.电子产品最好都不要长时间不用

拿张A4纸打印或者复印几下看个清楚。。看硒鼓打印出来字体是否饱满判断硒鼓寿命，现在硒鼓一个一般400块钱，打印长了一般没问题 就是换硒鼓

Daxing spring greenhouse grafted eggplant typical high yield experience First listing to the beginning of July, harvest 60d, an average of 667m capacity 7550kg, value of 9860 yuan, output value are ranked first in the region. 4m and exposed to relatively low tunnel grafting eggplant, each 667nl yield 2065kg,abercrombie milano Huixin net effect of Pieris ant, an increase of 37.6%, the output value increased 2839 yuan, an increase of 40.4%. Summarize the successful experience of the following points: a new technology used in all root grafting technique, which is one of the key high-yield. Eggplant grafting is the use of wild eggplant rootstock, the tomato seedlings grafted on rootstock of a technology. Eggplant grafting developed root system, with disease resistance, strong growth potential, longer growing season, to improve the quality, etc., increase production effect is remarkable. Second, the introduction of new varieties of rootstock varieties used are Toto Alaska. Good affinity with the scions of the varieties developed root system, can improve the quality of scion, especially in the late growing strong, fast growing, upright and strong, high yield, good quality. The use of early maturing varieties of eggplant scion Beijing No. 1. The variety is Vegetable Research Center, Beijing Academy of Agriculture and bred new varieties of eggplant,Ralph Lauren, the biggest advantage is easy to fruit set, fruit development faster, less deformed fruit; upright plant type, compact, Qi Yan flowers, vegetables, Beijing Daxing District People's Government Office, 102 600 Wang Xue-Cai, Daxing District, Beijing Agriculture Committee, 102600 Zhao Guanghua, Zhang Haifang, mailing address with the first author Qi Yan-Hua Wang, Xue-Cai Zhao Guanghua Zhang Haifang continuous outcome is good, pre-production focus, especially for protected production, but also to adapt to early spring exposed to a small shed mulching ; nearly spherical fruit, fruit color Zihei shiny,Ralph Lauren, light green flesh white, especially good character goods; average number of results to plant 8 to 10, the maximum gate tomato fruit weight 1.25kg. Third, the suitable period of colonization, picked early in Beijing greenhouse grafted eggplant appropriate planting period on or about March 20, exposed to 4m with a comparison of early colonization Small Shed 15 ~ 20d. Thus, in early May spring greenhouse grafted eggplant can be harvested, can be listed ahead of 15 ~ 20d. Easy to fall because the door eggplant seedlings,Ralph Lauren, timely harvest. When the eggplant is generally attached to sepals and fruits at the light-colored ring with a narrow or not apparent, that the fruit has been growing slowly, this time to harvest market. Fourth, the rational management of basal fertilizer should be sufficient for every 667m. Shi-quality decomposition of organic fertilizer 5000 ~ 6000kg, high levels of NPK NPK 50kg. First 2 / 3 of fertilizer spread on the surface diffuse, Rotary 1 times, the loam mix, and then planting spacing 75cm ditching the remainder of the fertilizer is one trench. Enlargement of the door to harvest eggplant end, 10d around water a fertilizer. Irrigation, fertilizer and water alternately, to ensure that fruit enlargement and development. Fertilizer per 667m2 water per 15 to 20 (high potassium). Spraying every 7 ~ 10d 0.3% potassium dihydrogen phosphate or other fertilizer to ensure supply of potash. Fifth, to enhance pest control is necessary to seriously implement the The main diseases of grafted eggplant brown grain and cotton disease and other diseases, insect pests are red spider, yellow tea mite, cotton bollworm. With 80% WP Mancozeb 72% of 500 times or 700 times S & P Lectra agent, can prevent disease and grain brown cotton diseases. Spider, yellow tea mite, cotton bollworm available abamectin 1.8% EC or 70% of 2500 times propargite EC 1500 times of spraying. Eliminate the use of, the highly toxic and residual pesticide,Ralph Lauren, pesticide safety interval of execution, to ensure quality and safety of vegetables. With mildew, rust, powdery mildew and aphids, whitefly. Anthrax anthrax in the early stages with 80% or 50% thiophanate Fumei WP 800 times control, 45% chlorothalonil also be smoke each 667m250 ~ 300g smoked control. Leaf mold with a 77% or 75% killing chlorothalonil or 50% carbendazim WP 600 ~ 800 times, it can be 50% or 50% Iprodione WP procymidone Prevention from 1000 to 1500-fold . Rust and powdery mildew, 25% Triadimefon WP can be used 1500 times or 5010 Carboxin WP 1000 times control. 50% of aphids can be provision of aphid fog WP 2000 times, or 22% DDV smoke every 667m300g control. Whitefly with 25% Buprofezin WP 2000 to 2500 times or 1000 times the EC 50% DDV control. Seven timely harvest It was observed that under normal circumstances, beans flowering the first 14 ~ 15d after the length and fresh weight of pods have reached the maximum, so this time picking the highest yield and quality is the best. Timely harvest, market supply, in order to obtain high returns. With the