キャラクターをスクリーン内で動かすゲームを作りたいが、画面が更新されず、キャラクターの残像が残ってしまう。（pygame)

前提

初めての質問です。
ウインドウ内にキャラクターを表示させ、キー操作に応じて動かすプログラムを作成中です。

キャラクター表示、キー操作に応じて動くところまではできていますが、
前の画像がずっと残ったままで、動いた軌跡がそのまま画像として残り、
残像みたいになってしまいます。

実現したいこと

残像が残らないよう画面を更新したい（キャラクターを動かしたい）。

発生している問題・エラーメッセージ

エラーにはならないです。

該当のソースコード

python
1import pygame, time
2import sys
3from pygame.locals import *
4
5window = pygame.display.set_mode((800, 600))
6
7def main():
8    quit = False
9    pygame.init()
10    window.fill((pygame.Color("BLACK")))
11    
12    y_ground = window.get_height() - 100
13
14    x = 145
15    y = y_ground
16
17    player_stand = pygame.image.load("assets/p1_stand.png").convert_alpha()
18    player_stand = pygame.transform.scale(player_stand, (50, 70))
19
20    player_right = [
21
22        pygame.image.load("assets//p1_walk/PNG//p1_walk01.png").convert_alpha(),
23        pygame.image.load("assets//p1_walk/PNG//p1_walk02.png").convert_alpha(),
24        pygame.image.load("assets//p1_walk/PNG//p1_walk03.png").convert_alpha(),
25        pygame.image.load("assets//p1_walk/PNG//p1_walk04.png").convert_alpha(),
26        pygame.image.load("assets//p1_walk/PNG//p1_walk05.png").convert_alpha(),
27        pygame.image.load("assets//p1_walk/PNG//p1_walk06.png").convert_alpha(),
28        pygame.image.load("assets//p1_walk/PNG//p1_walk07.png").convert_alpha(),
29        pygame.image.load("assets//p1_walk/PNG//p1_walk08.png").convert_alpha(),
30        pygame.image.load("assets//p1_walk/PNG//p1_walk09.png").convert_alpha(),
31        pygame.image.load("assets//p1_walk/PNG//p1_walk10.png").convert_alpha(),
32        pygame.image.load("assets//p1_walk/PNG//p1_walk11.png").convert_alpha() 
33    ]
34
35    player_right = [pygame.transform.scale(image,(50,70))
36                        for image in player_right]
37
38    player_left = [pygame.transform.flip(image, True, False)   
39                   for image in player_right ]
40
41    player_jump = pygame.image.load("assets/p1_jump.png").convert_alpha()
42    player_jump = pygame.transform.scale(player_jump,(50,70))
43
44    player_jump_frame = 0
45
46    player_landing = pygame.image.load("assets/p1_duck.png").convert_alpha()
47    player_landing = pygame.transform.scale(player_landing,(50,70))
48
49    player_right_frame = 0                                          
50    player_left_frame = 0
51    
52    keyspressed = pygame.key.get_pressed()                          
53                                                                    
54    window.blit(player_stand,(x,y))
55     
56
57    while not quit:
58        key = pygame.key.get_pressed()                              
59                                     
60        if key[pygame.K_RIGHT]:
61            x = x + 50
62            direction = "right"
63
64        elif(key[pygame.K_LEFT]):
65            x = x - 50
66            direction = "left"
67
68        elif(key[pygame.K_UP]):
69            if y == y_ground:
70                player_jump_frame = 10                                 
71
72        elif(key[pygame.K_DOWN]):                       
73            y = y + 10                               
74            direction = "landing"
75
76        elif sum(keyspressed) == 0: 
77            direction = "standing"
78
79        if player_jump_frame > 0:
80            y = y - 10
81            direction = "jump"
82            player_jump_frame = player_jump_frame - 1
83
84        elif y < y_ground:
85            direction = "landing"
86            y = y + 10
87                             
88
89        if direction == "right":
90            window.blit(player_right[player_right_frame], (x,y))
91            player_right_frame = (player_right_frame + 1) % len(player_right)
92            
93        elif direction == "left":
94            window.blit(player_left[player_left_frame], (x,y))
95            player_left_frame = (player_left_frame + 1) % len(player_left)        
96         
97        elif direction == "jump":
98            window.blit(player_jump, (x,y))
99
100        elif direction == "landing":
101            window.blit(player_landing, (x,y))
102
103        clock.tick(15)                                 
104        pygame.display.update()
105
106        for event in pygame.event.get():
107            if event.type == QUIT:
108                quit = True
109
110 
111if __name__ == "__main__":
112    width, height = 800, 600                            
113    pygame.init()                                       
114    pygame.mixer.init()                                 
115    window = pygame.display.set_mode((width, height))   
116    clock = pygame.time.Clock()                        
117    main()
118    pygame.quit()